61721313 has 8 divisors (see below), whose sum is σ = 82848000. Its totient is φ = 40871088.

The previous prime is 61721273. The next prime is 61721321. The reversal of 61721313 is 31312716.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 61721313 - 2⁸ = 61721057 is a prime.

It is not an unprimeable number, because it can be changed into a prime (61721323) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 68593 + ... + 69486.

It is an arithmetic number, because the mean of its divisors is an integer number (10356000).

Almost surely, 2^61721313 is an apocalyptic number.

It is an amenable number.

61721313 is a deficient number, since it is larger than the sum of its proper divisors (21126687).

61721313 is a wasteful number, since it uses less digits than its factorization.

61721313 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 138231.

The product of its digits is 756, while the sum is 24.

The square root of 61721313 is about 7856.2913006074. The cubic root of 61721313 is about 395.1952525047.

The spelling of 61721313 in words is "sixty-one million, seven hundred twenty-one thousand, three hundred thirteen".